Mold Partial Surface Dies Fiber Orientation Thermal Expansion

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Solution Overview

Problem

The challenge arises when using different materials for the core die and partial surface die in aircraft skin panel molding, leading to thermal expansion differences that cause wrinkles in the laminate, reducing the strength of the skin panel.

Innovation Solution

A mold configuration where the partial surface dies are made of fiber-reinforced resin with a higher fiber quantity in the circumferential direction to match the core die's thermal expansion coefficient, minimizing wrinkles by controlling the fiber orientation and distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If different materials are used for the core die and partial surface die, then the core die has long durability and the partial surface die has high smoothness, but thermal expansion differences cause wrinkles in the laminate

Engineering Contradiction:

Improvedurability of core dieVSAvoidsmoothness of skin panel

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the material composition parameters of the partial surface die by incorporating fiber-reinforced resin with specific fiber orientations. The fiber arrangement is designed to control the coefficient of thermal expansion in the circumferential direction, making it match that of the metal core die, thereby preventing wrinkles during curing

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials (fiber-reinforced resin) for the partial surface die instead of traditional single materials. This composite structure allows tuning of thermal expansion properties through fiber orientation and distribution, enabling compatibility with the metal core die while maintaining smoothness

Inventive Principle:

Principle #40Composite materials

2Area of stationary object

If a plurality of partial surface dies are assembled to construct the mold, then the mold can accommodate large diameter skin panels, but edges of partial surface dies press against the laminate causing intrusion

Engineering Contradiction:

Improvediameter of skin panelVSAvoidintegrity of laminate

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent employs fiber-reinforced resin for the partial surface dies, which provides a balance between rigidity (to maintain shape) and flexibility (to accommodate thermal expansion without pressing into the laminate). This material choice prevents edge intrusion while still enabling the assembly of multiple dies for large diameter panels

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If fiber-reinforced resin is used for partial surface die, then thermal expansion can be matched with core die, but the material requires precise fiber orientation control

Engineering Contradiction:

Improvethermal expansion compatibilityVSAvoidfiber orientation control

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies different fiber orientations in different regions of the partial surface die. Specifically, fibers are arranged with their grain directions aligned in the circumferential direction to control thermal expansion in that direction, while allowing different orientations in other directions. This localized fiber arrangement achieves thermal compatibility without requiring complex control throughout the entire structure

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration effectively suppresses wrinkles during the curing process, maintaining the strength and smoothness of the skin panel by aligning the thermal expansion coefficients of the partial surface dies with the core die, thereby preventing strength reduction.

Implementation Method 1

each of the partial surface dies being constructed such that a coefficient of thermal expansion in the circumferential direction more closely approximates a coefficient of thermal expansion of the core die than a coefficient of thermal expansion in the axial direction

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10118316B2Mold

Publication Date: 2018.11.06 KAWASAKI JUKOGYO KK

AI summary

A method of adjusting a coefficient of thermal expansion of a member made of a fiber-reinforced resin, the method including: adjusting a coefficient of thermal expansion in a predetermined direction by increasing or decreasing a quantity of fiber having a grain direction in agreement with the predetermined direction. Also disclosed is a mold (100) for curing a cylindrical laminate (30) obtained by laminating prepreg. The mold includes a core die (10) and a surface die (2) outside the laminate including a plurality of partial surface dies (21 to 27). The partial surface dies are arranged to cover the entire circumferential surface of the laminate. Each of the partial surface dies is made of a fiber-reinforced resin in which a quantity of fiber having a grain direction in agreement with the circumferential direction differs from a quantity of fiber having a grain direction in agreement with an axial direction.